1. Field of the Invention
The disclosed invention generally relates to data storage and more specifically to an interface for local and network data storage.
2. Background Art
In the field of information technology, the terms “storage” or “memory” refer to media that retain data for some interval of time, possibly even after electrical power to the computer is turned off. In a business or personal computer system, storage often takes the form of either a hard disk, random access memory (RAM) or cache memory. A hard disk stores the user's files and programs even if the computer is turned off, and has a large capacity. RAM is used to store information such as programs and data temporarily while the computer is using them. RAM can be accessed at very high speeds, which makes it suitable for applications, however RAM used for these purposes is typically volatile and all information in it is lost when the computer is turned off. Cache memory, is often built into the microprocessor, hard drives, or other devices, providing high speed dedicated memory to minimize repeated access to slower storage devices.
There are many applications, particularly in a business environment, where there are needs beyond what can be fulfilled by a single hard disk, regardless of its size, performance or quality level. Many businesses can't afford to have their systems go down for even an hour in the event of a disk failure. They need large storage subsystems with capacities in the terabytes. And they want to be able to insulate themselves from hardware or software failures to any extent possible. Some people working with multimedia files need fast data transfer exceeding the speeds current drives can deliver, without spending a fortune on specialty drives. These situations require that the traditional “one hard disk per system” model be set aside and a new system employed. One popular technique is known as Redundant Arrays of Inexpensive (or Independent) Disks, or RAID. See D. Patterson, G. Gibson, and R. Katz. “A Case for Redundant Array of Inexpensive Disks (RAID)”, Proceedings of ACM SIGMOD '88, pages 109-116, June 1988.
Data can also be stored in storage systems over a network. This option may be attractive due to spatial and/or financial constraints involved with implementing a dedicated storage system for each individual in a group or to facilitate sharing of data among members of a group. Sharing storage usually simplifies storage administration and adds flexibility since cables and storage devices do not have to be physically moved to move storage from one server to another.
Currently computer system I/O boards have any of a local storage controller interface (such as Advanced Technology Attachment (ATA), Integrated Drive Electronics (IDE), Serial ATA (SATA), Small Computer System Interface (SCSI), RAID, Serial Attached SCSI (SAS) or Enhanced IDE (EIDE) etc.) to access local storage or a network interface, such as 10/100 Mbps network cards or gigabit Ethernet network cards, to access network storage via network storage protocols such as internet Small Computer System Interface (iSCSI) or Fibre Channel (FC). As distinct interfaces, the hardware cards and software interfaces are managed separately by the operating system (OS) and the user interacts with each associated storage system individually. However, distinct local and remote networked storage units do not provide the same functionality or capabilities that can be delivered by a single local storage unit. The inventors have found that there is a need for improved data storage interfaces.